In general, a high-voltage battery is used in an electric vehicle or a fuel battery vehicle as well as a hybrid vehicle to supply electric energy for driving a vehicle.
In the high-voltage battery, a battery package is configured, which may generate high voltage by connecting a plurality of unit batteries or modules and high power is generated by using the configured battery package.
A rectangular or pouch type battery which may be stacked with high integration and has a small weight compared to a capacity is primarily used for the battery pack, and lithium ion batteries that provide high power compared to the capacity are a lot used as the unit battery (battery cell) of the battery package.
However, the lithium ion battery has a problem that safety is fundamentally low, and the pouch type battery has a problem that mechanical rigidity of a battery case is low and when a sealed part is separated, an ignitable substance such as an electrolyte leaks, and as a result, a risk of fire is high.
In particular, since the electrolyte is injected into the cell, when the battery is overcharged, voltage is increased and the electrolyte in the cell is resolved due to overheat and combustible gas is thus internally generated in the cell, and as a result, a swelling phenomenon in which a pouch itself is expanded occurs. Therefore, ignition and explosion risks of the battery are increased.
Therefore, a technology for forcibly cutting off the power of the battery is proposed when the swelling phenomenon occurs due to the overcharge of the battery.